The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The triazine network structure formed upon curing cyanate ester materials exhibits a balance of flexibility, low dielectric loss, low moisture pick-up, and thermal stability in the absence of water that makes these materials suitable for use in high-end microelectronics packaging, multi-layer circuit boards and aerospace composite applications. Currently, cyanate ester materials are used for the lamination of substrates in high density, high speed multi-layer electronic boards.
However, in addition to several useful properties, cyanate ester chemistry also exhibits multiple drawbacks or limitations. A summary of the advantages and disadvantages of using cyanate ester materials is provided in Table 1. One deficiency of cyanate ester chemistry is its low thermal-hydrolytic stability, which mainly manifests itself as reversion of the triazine bond upon high temperature water exposure. So, even though the triazine network is considered to be hydrophobic, especially if compared to the high moisture absorption (i.e., 1.5 to 4%) common in epoxy resins, the degradation that occurs at high temperature in the presence of trace amounts of water becomes a major issue.
Table 1. Advantages & Disadvantages of Cyanate Ester Materials.
ADVANTAGESDISADVANTAGESEasy to processHigh costVersatile reactivityThermo-hydrolytic stabilityHigh service temperatureDielectric loss can improveTough - FlexibleFire resistanceLow dielectric lossAdhesion issuesLow moisture absorptionLow Coefficient of ThermalExpansion (CTE)